Typical probes used for signal acquisition and analysis devices such as oscilloscopes and the like have an impedance associated with them which varies with frequency. As the bandwidth of test and measurement instruments and probe system become wider the effects of probe tip loading of non-flat through responses becomes more significant than in past systems.
U.S. Pat. No. 6,725,170 entitled “Smart probe apparatus and method for automatic self-adjustment of an oscilloscope's bandwidth” to Barton Hickman, owned by Tektronix, Inc. and incorporated herein by reference, discloses storing S-parameters of a probe so that equalization filters can be computed when a probe is connected to different input channels of different types of test and measurement instruments. These equalization filters, however, are designed for device under test (DUT) source impedance of 50 ohms. What is needed is an equalization filter that can be calculated using the nominal source impedance of the DUT. Using the prior methods, if the source impedance of the DUT is not 50 ohms, then the acquired waveform received via a probe loading such a circuit may not accurately represent the voltage of the circuit prior to the introduction of the probe.